Newbie question Common Lisp generic functions

Hi /prog/, this may disappoint you but this is a thread about programming... But it's written by a guy who wants help !
Basically, my question is:
With a generic function and its methods one can check the type/class of the variables that the genfun receives and the genfun therefore chooses the appropiate method, is there any possibility to make it check for the appropiate symbol?

If I can't make it check for the appropiate symbol, am I then forced to simply write one function with many cases?

OP here. I decided to annoy you anyway.